As a woman who travels alone a lot, I look for security gadgets, and First Alert's lightweight alarm is, if nothing else, piercingly earsplitting. While the alarm's not loud enough to be heard a block away, it's going to get the attention of anyone nearby. It only weighs about an ounce (with the included lithium battery), and I found it to be ergonomically well designed to fit in my hand without blocking the alarm's speaker. The wrist strap can be looped over doorknobs, suitcase handles, camera or purse straps, where the movement sensor can be set to go off instantly or with a 30-second delay. (The delay setting is for hanging it from the doorknob inside your hotel room when you go out so you have half-a-minute to get into the room and turn it off before the screeching alarm starts.)

What worked: The 100-dB alarm is certainly unnerving, which is to say it works well. The integrated LED flashlight's a nice touch.

Not so much: The buttons don't seem to be recessed enough to prevent hitting them by accident.